Filter pressure and variable speed pumps
Another challenge with filtration systems and filter pressure has come to light with the advent of variable-speed pumps (VSPs).
“In the past, the pump was either on or off and service technicians took the psi measurement when the pump was on,” says Fowler. “As these pumps do not constantly run at full speed it becomes harder to get an accurate psi reading because as flow increases, pressure also increases, but not necessarily because the filter is dirty.”
According to Lenz, one of the best practices used today is to have the client turn their pump to full-speed once a week and take note of the psi at this time.
“We tell our customers to keep a log on their filter and to call us when the psi increases beyond 2.25 kg (5 lbs),” he says. “This is now a part of the weekly maintenance we recommend to clients, along with cleaning the filter baskets, skimmer, etc.
“In the past, it was common to watch the psi reading and if there was a 4.5 kg (10 lbs) increase, it was time to backwash (i.e. clean) the filter,” Fowler adds.
“With cartridge filters, however, it’s safer to advise cleaning the filter when there is a 2.25 kg (5 lbs) increase in pressure,” he says. “Sticking to this rule of thumb can prolong the life of the filter. If the pool owner waits for a 4.5 kg (10 lbs) change in pressure, the pleats will begin to collapse and the bands will start to break.”
Automatic controllers
An automation system can be beneficial when it comes to alerting the homeowner or service technician when a dirty sand filter may need to be backwashed.
“Rather than having to perform manual checks weekly, an automatic controller can also be used to set a backwash schedule based on psi readings,” says Fowler.
That said, automatic controllers can be an invaluable addition to a pool’s filtration system. With an automatic backwash controller, the need for a service technician to be present to perform this maintenance procedure—although recommended—is not necessary because the parameters set in the controller will automate the backwash process when it is time to do so.
“Most backwash cycles will occur when you see a 10 to 15 psi increase from starting clean filter pressure,” says Fowler. “Automatic controllers can be set to backwash the filter when this pressure increases, while some units can be programmed to backwash on a specific day of the week or time of day. Additional backwash controllers are also available and, although automated, require someone to activate the controller.”
Aimée Samuelson, MBA is president of B2B Marketing Solutions LLC, a specialty marketing firm with more than 25 years’ experience in the aquatics and construction industries. In addition to working in the pool and spa/hot tub sector, she has clients in the landscaping, stormwater, and industrial water treatment markets. Samuelson holds an MBA from the Foster School of Business at the University of Washington in Seattle, Wash., with additional business credentials from the Pontificia Universidad Católica de Chile in Santiago, Chile. She can be reached via e-mail at aimee@b2bmarket.us.
